fix(Threading): add thread priorities for better input performance

addons/linuxthread/linuxthread.gdextension

@@ -0,0 +1,9 @@
+[configuration]
+
+entry_symbol = "linux_thread_library_init"
+compatibility_minimum = 4.1
+
+[libraries]
+
+linux.debug.x86_64 = "res://addons/linuxthread/bin/liblinuxthread.linux.template_debug.x86_64.so"
+linux.release.x86_64 = "res://addons/linuxthread/bin/liblinuxthread.linux.template_release.x86_64.so"

core/systems/threading/input_thread.tres

@@ -6,3 +6,4 @@
 script = ExtResource("1_rbhla")
 name = "InputThread"
 target_tick_rate = 600
+niceness = -20

core/systems/threading/io_thread.tres

@@ -6,3 +6,4 @@
 script = ExtResource("1_qvlys")
 name = "IOThread"
 target_tick_rate = 30
+niceness = 0

core/systems/threading/shared_thread.gd

@@ -12,6 +12,7 @@ const watchdog := preload("res://core/systems/threading/watchdog_thread.tres")
 
 var thread: Thread
 var mutex := Mutex.new()
+var tid := -1
 var running := false
 var nodes: Array[NodeThread] = []
 var process_funcs: Array[Callable] = []
@@ -24,6 +25,8 @@ var logger := Log.get_logger("SharedThread", Log.LEVEL.INFO)
 @export var name := "SharedThread"
 ## Target rate to run at in ticks per second
 @export var target_tick_rate := 60
+## Priority (niceness) of the thread
+@export var niceness := 0
 
 
 func _init() -> void:
@@ -42,7 +45,7 @@ func start() -> void:
 	running = true
 	thread = Thread.new()
 	thread.start(_run)
-	logger.info("Thread group started: " + name)
+	logger.info("Shared thread started: " + name)
 
 
 ## Stops the thread for the thread group
@@ -53,7 +56,28 @@ func stop() -> void:
 	running = false
 	mutex.unlock()
 	thread.wait_to_finish()
-	logger.info("Thread group stopped: " + name)
+	logger.info("Shared thread stopped: " + name)
+
+
+## Set the given thread niceness to the given value.
+## Note: in order to set negative nice value, this must be run:
+## setcap 'cap_sys_nice=eip' <opengamepadui binary>
+func set_priority(value: int) -> int:
+	# If this was called from another thread, schedule it to run on the thread
+	mutex.lock()
+	var thread_id := tid
+	mutex.unlock()
+	if LinuxThread.get_tid() != thread_id:
+		logger.debug("Set thread priority was called from another thread")
+		return await exec(set_priority.bind(value))
+
+	# Set the thread priority if this function was called from the SharedThread
+	var err := LinuxThread.set_thread_priority(value)
+	if err == OK:
+		niceness = value
+		logger.info("Set thread niceness on {0} ({1}) to: {2}".format([name, thread_id, value]))
+
+	return err
 
 
 ## Add the given [NodeThread] to the list of nodes to process. This should
@@ -145,6 +169,17 @@ func remove_process(method: Callable) -> void:
 
 
 func _run() -> void:
+	# Update the thread ID
+	mutex.lock()
+	tid = LinuxThread.get_tid()
+	mutex.unlock()
+	logger.info("Started thread with thread ID: " + str(LinuxThread.get_tid()))
+
+	# If the nice value isn't default, reassign the thread priority
+	if niceness != 0:
+		if await set_priority(niceness) != OK:
+			logger.warn("Unable to set niceness on thread: " + name)
+
 	# TODO: Fix unsafe thread operations
 	Thread.set_thread_safety_checks_enabled(false)
 	var exited := false

core/systems/threading/system_thread.tres

@@ -6,3 +6,4 @@
 script = ExtResource("1_hqprx")
 name = "SystemThread"
 target_tick_rate = 600
+niceness = 0

core/systems/threading/utility_thread.tres

@@ -6,3 +6,4 @@
 script = ExtResource("1_svd22")
 name = "UtilityThread"
 target_tick_rate = 10
+niceness = 0

core/systems/threading/watchdog_thread.tres

@@ -6,3 +6,4 @@
 script = ExtResource("1_fg543")
 name = "WatchdogThread"
 target_tick_rate = 1
+warn_after_num_missed_frames = 20

entrypoint.gd

@@ -129,6 +129,10 @@ func _apply_update_packs() -> void:
 			if OS.execute("chmod", ["+x", file_path]) != OK:
 				logger.warn("Failed to set execute permissions. Not loading update pack")
 				return
+
+			# Try to run setcap to allow setting thread priorities
+			if OS.execute("/usr/share/opengamepadui/scripts/make_nice", []) != OK:
+				logger.warn("Unable to run setcap to enable thread priorities")
 
 	# Launch the update pack executable and exit
 	var update_bin := ProjectSettings.globalize_path(update_pack_entrypoint)

rootfs/Makefile

@@ -21,21 +21,34 @@ install: ## Install OpenGamepadUI (default: ~/.local)
 	install -Dm644 usr/share/icons/hicolor/scalable/apps/opengamepadui.svg \
 		$(PREFIX)/share/icons/hicolor/scalable/apps/opengamepadui.svg
 	mkdir -p $(PREFIX)/share/opengamepadui
+	install -Dm644 usr/share/opengamepadui/libdbus.linux.template_debug.x86_64.so \
+		$(PREFIX)/share/opengamepadui/libdbus.linux.template_debug.x86_64.so
 	install -Dm644 usr/share/opengamepadui/libevdev.linux.template_debug.x86_64.so \
 		$(PREFIX)/share/opengamepadui/libevdev.linux.template_debug.x86_64.so
-	install -Dm644 usr/share/opengamepadui/libxlib.linux.template_debug.x86_64.so \
-		$(PREFIX)/share/opengamepadui/libxlib.linux.template_debug.x86_64.so
+	install -Dm644 usr/share/opengamepadui/liblinuxthread.linux.template_debug.x86_64.so \
+		$(PREFIX)/share/opengamepadui/liblinuxthread.linux.template_debug.x86_64.so
 	install -Dm644 usr/share/opengamepadui/libopensd.linux.template_debug.x86_64.so \
 		$(PREFIX)/share/opengamepadui/libopensd.linux.template_debug.x86_64.so
 	install -Dm644 usr/share/opengamepadui/libpty.linux.template_debug.x86_64.so \
 		$(PREFIX)/share/opengamepadui/libpty.linux.template_debug.x86_64.so
+	install -Dm644 usr/share/opengamepadui/libxlib.linux.template_debug.x86_64.so \
+		$(PREFIX)/share/opengamepadui/libxlib.linux.template_debug.x86_64.so
 	install -Dm755 usr/share/opengamepadui/opengamepad-ui.x86_64 \
 		$(PREFIX)/share/opengamepadui/opengamepad-ui.x86_64
+	setcap 'cap_sys_nice=eip' $(PREFIX)/share/opengamepadui/opengamepad-ui.x86_64 || true
 	mkdir -p $(PREFIX)/share/opengamepadui/scripts
 	install -Dm755 usr/share/opengamepadui/scripts/powertools \
 		$(PREFIX)/share/opengamepadui/scripts/powertools
+	install -Dm755 usr/share/opengamepadui/scripts/manage_input \
+		$(PREFIX)/share/opengamepadui/scripts/manage_input
+	install -Dm755 usr/share/opengamepadui/scripts/make_nice \
+		$(PREFIX)/share/opengamepadui/scripts/make_nice
 	install -Dm644 usr/share/polkit-1/actions/org.shadowblip.powertools.policy \
 		$(PREFIX)/share/polkit-1/actions/org.shadowblip.powertools.policy
+	install -Dm644 usr/share/polkit-1/actions/org.shadowblip.manage_input.policy \
+		$(PREFIX)/share/polkit-1/actions/org.shadowblip.manage_input.policy
+	install -Dm644 usr/share/polkit-1/actions/org.shadowblip.setcap.policy \
+		$(PREFIX)/share/polkit-1/actions/org.shadowblip.setcap.policy
 	install -Dm644 usr/lib/udev/hwdb.d/59-opengamepadui-handheld.hwdb \
 		$(PREFIX)/lib/udev/hwdb.d/59-opengamepadui-handheld.hwdb
 	install -Dm644 usr/lib/udev/rules.d/61-opengamepadui-handheld.rules \

rootfs/usr/share/opengamepadui/scripts/make_nice

@@ -0,0 +1,10 @@
+#!/bin/bash
+set -eu
+
+if [[ $EUID -ne 0 ]]; then
+  exec pkexec --disable-internal-agent "$0" "$HOME" "$@"
+fi
+
+USER_HOME="$1"
+UPDATE_PATH="${USER_HOME}/.local/share/opengamepadui/updates/opengamepad-ui.x86_64"
+setcap 'cap_sys_nice=eip' "${UPDATE_PATH}"

rootfs/usr/share/polkit-1/actions/org.shadowblip.setcap.policy

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN" "http://www.freedesktop.org/standards/PolicyKit/1/policyconfig.dtd">
+<policyconfig>
+  <vendor>ShadowBlip</vendor>
+  <vendor_url>http://www.github.com/shadowblip</vendor_url>
+  <action id="org.shadowblip.pkexec.setcap">
+    <description>Allow negative nice values</description>
+    <icon_name>package-x-generic</icon_name>
+    <defaults>
+      <allow_any>yes</allow_any>
+      <allow_inactive>yes</allow_inactive>
+      <allow_active>yes</allow_active>
+    </defaults>
+    <annotate key="org.freedesktop.policykit.exec.path">/usr/share/opengamepadui/scripts/make_nice</annotate>
+  </action>
+</policyconfig>